Abstract: DESCRIPTION: (adapted from the application): The earlier work of this investigator, within this Program Project, challenges long-held beliefs about the demography of aging. The large scale experimental studies have shown that for five species, mortality decelerates at older ages. The generality of these conclusions, and the causes of these mortality patterns as reflected in individual life-course dynamics, needs to be determined. The plant species Plantago lanceolata offers a unique experimental system to monitor a large population of individuals under the conditions which evolutionary forces have been acting on for generations. This study is designed to determine the details of the mortality trajectory late in life in order to identify whether mortality deceleration occurs in a natural population. In addition, with information on age-specific morality and reproduction for each individual, these investigators will be able to determine details of the life history including the correlations between mortality and reproduction, and the age- specific allocation panems between reproduction and growth. This data will also be used to test assumptions of the current evolutionary theories of senescence. In addition, this experimental system allows us the unique opportunity to use genetic clones of preserved individuals to complete our analysis of the life-course dynamics in order to determine if there are unique factors which contribute to the extraordinary longevity of the 'oldest-old'.